DES-EDE3-OFB ENCRYPTION TOOL

Other Crypto Algorithms

AES-128-CBC AES-128-CBC-CTS AES-128-CBC-HMAC-SHA1 AES-128-CBC-HMAC-SHA256 AES-128-CCM AES-128-CFB AES-128-CFB1 AES-128-CFB8 AES-128-CTR AES-128-ECB AES-128-GCM AES-128-GCM-SIV AES-128-OCB AES-128-OFB AES-128-SIV AES-128-WRAP AES-128-WRAP-INV AES-128-WRAP-PAD AES-128-WRAP-PAD-INV AES-128-XTS AES-192-CBC AES-192-CBC-CTS AES-192-CCM AES-192-CFB AES-192-CFB1 AES-192-CFB8 AES-192-CTR AES-192-ECB AES-192-GCM AES-192-GCM-SIV AES-192-OCB AES-192-OFB AES-192-SIV AES-192-WRAP AES-192-WRAP-INV AES-192-WRAP-PAD AES-192-WRAP-PAD-INV AES-256-CBC AES-256-CBC-CTS AES-256-CBC-HMAC-SHA1 AES-256-CBC-HMAC-SHA256 AES-256-CCM AES-256-CFB AES-256-CFB1 AES-256-CFB8 AES-256-CTR AES-256-ECB AES-256-GCM AES-256-GCM-SIV AES-256-OCB AES-256-OFB AES-256-SIV AES-256-WRAP AES-256-WRAP-INV AES-256-WRAP-PAD AES-256-WRAP-PAD-INV AES-256-XTS ARIA-128-CBC ARIA-128-CCM ARIA-128-CFB ARIA-128-CFB1 ARIA-128-CFB8 ARIA-128-CTR ARIA-128-ECB ARIA-128-GCM ARIA-128-OFB ARIA-192-CBC ARIA-192-CCM ARIA-192-CFB ARIA-192-CFB1 ARIA-192-CFB8 ARIA-192-CTR ARIA-192-ECB ARIA-192-GCM ARIA-192-OFB ARIA-256-CBC ARIA-256-CCM ARIA-256-CFB ARIA-256-CFB1 ARIA-256-CFB8 ARIA-256-CTR ARIA-256-ECB ARIA-256-GCM ARIA-256-OFB CAMELLIA-128-CBC CAMELLIA-128-CBC-CTS CAMELLIA-128-CFB CAMELLIA-128-CFB1 CAMELLIA-128-CFB8 CAMELLIA-128-CTR CAMELLIA-128-ECB CAMELLIA-128-OFB CAMELLIA-192-CBC CAMELLIA-192-CBC-CTS CAMELLIA-192-CFB CAMELLIA-192-CFB1 CAMELLIA-192-CFB8 CAMELLIA-192-CTR CAMELLIA-192-ECB CAMELLIA-192-OFB CAMELLIA-256-CBC CAMELLIA-256-CBC-CTS CAMELLIA-256-CFB CAMELLIA-256-CFB1 CAMELLIA-256-CFB8 CAMELLIA-256-CTR CAMELLIA-256-ECB CAMELLIA-256-OFB CHACHA20 CHACHA20-POLY1305 DES-EDE-CBC DES-EDE-CFB DES-EDE-ECB DES-EDE-OFB DES-EDE3-CBC DES-EDE3-CFB DES-EDE3-CFB1 DES-EDE3-CFB8 DES-EDE3-ECB DES-EDE3-OFB DES3-WRAP

The DES-EDE3-OFB algorithm is a symmetric key block cipher that employs the Data Encryption Standard (DES) in a triple encryption configuration combined with the Output Feedback (OFB) mode of operation. The "EDE3" designation stands for "Encrypt-Decrypt-Encrypt with three independent keys," indicating that the data undergoes three sequential DES operations using three distinct keys. This structure enhances security compared to single DES by effectively increasing the key length to 168 bits, reducing susceptibility to brute-force attacks.

Key Structure

DES-EDE3-OFB uses three independent keys, each 56 bits in length. The three keys are applied in the following sequence: the plaintext is first encrypted with Key1, then decrypted with Key2, and finally encrypted with Key3. This triple application ensures compatibility with single DES for backward compatibility when all three keys are identical.

Block and Feedback Mode

The algorithm operates on 64-bit blocks, which is standard for DES. In OFB mode, an initial vector (IV) is used to generate a keystream independent of the plaintext. Each subsequent block of the keystream is produced by encrypting the previous output of the DES operation. The plaintext is XORed with the generated keystream to produce ciphertext. This feedback mode prevents error propagation, meaning a bit error in the ciphertext affects only the corresponding bit in the decrypted plaintext.

Encryption Process

1. Initialize the 64-bit IV.
2. Apply DES encryption using Key1 on the IV to produce the first output block.
3. Apply DES decryption using Key2 on the first output block.
4. Apply DES encryption using Key3 on the result to generate the keystream block.
5. XOR the keystream block with the plaintext block to obtain the ciphertext block.
6. Repeat the process for subsequent blocks, feeding the previous output through the same sequence.

Security Properties

DES-EDE3-OFB combines the proven structure of DES with triple encryption and the OFB feedback mode. OFB mode ensures that identical plaintext blocks produce different ciphertext blocks when different IVs are used, improving resistance to pattern analysis. The triple encryption with independent keys significantly increases the computational effort required for exhaustive key search, while the OFB mode maintains synchronization between sender and receiver without error propagation.

Applications

This algorithm is primarily used in legacy systems requiring symmetric key encryption with strong protection against brute-force attacks. It is suitable for encrypting data streams where error propagation must be minimized, such as in communication channels and secure file storage. The deterministic nature of the OFB mode allows for precomputation of the keystream for performance optimization in repetitive encryption scenarios.

Any copying, distribution, or use of the materials from this service without authorization is strictly prohibited. Violations will be prosecuted under applicable law and may result in both civil and criminal liability.